WikiLeaks, which published more than 20 sets of Clinton campaign e-mails in October 2016 (in a dump known as “The Podesta Emails”) tweeted a copy of a letter dated 28 October 2016 and signed by FBI Director James Comey:

Aside from the letter and Chaffetz’s tweet, little was initially known about the impetus for the reinvestigation. There was some quibbling over whether the investigation was being “reopened” or restarted:

Clarifying: Comey doesn’t say the FBI is reopening the Clinton investigation per se, rather that it’s assessing newly found emails.

According to the Wall Street Journal, the new information came from electronic devices taken from Clinton aide Huma Abedin and her husband, Anthony Weiner, in the course of a separate investigation:

Federal agents are preparing to scour roughly 650,000 emails contained on the laptop of former Rep. Anthony Weiner to see how many relate to a prior probe of Hillary Clinton’s email use, as metadata on the device suggests there may be thousands sent to or from the private server that the Democratic nominee used while she was secretary of state, according to people familiar with the matter.

The review will take weeks at a minimum to determine whether those messages are work-related emails between Huma Abedin, a close Clinton aide and the estranged wife of Mr. Weiner, and State Department officials; how many are duplicates of emails already reviewed by the Federal Bureau of Investigation; and whether they include either classified information or important new evidence in the Clinton email probe, which FBI officials call “Midyear.”

The FBI has had to await a court order to begin reviewing the emails, because they were uncovered in an unrelated probe of Mr. Weiner, and that order was delayed for reasons that remain unclear.